Edema is the abnormal retention of fluid in a patient's body. The fluid may be retained in the patient's thorax, including in the patient's lungs and/or heart. Pulmonary edema is the retention of fluid in the patient's lungs. Pulmonary edema may cause shortness of breath in the patient and result in a need for emergency medical treatment or care.
Pulmonary edema may have a cardiac origin. For example, pulmonary edema may be caused by a cardiac disease. Congestive heart failure typically results in the myocardium of the heart being unable to pump out a sufficient amount of fluid from the heart. For example, the heart may be too weak to fully discharge blood that has accumulated in the heart. As time passes, the build up of fluid in the chambers of the heart causes the heart to be overloaded with the fluid. Excess fluid may drain into the lungs of the patient and cause or exacerbate the patient's pulmonary edema.
Pulmonary edema also may be caused, however, by other conditions unrelated to cardiac disease. For example, pulmonary edema may have a non-cardiac origin. Lung diseases such as emphysema may cause an increase in the build up of fluid in the lungs. This fluid build up may result in pulmonary edema.
The medical therapies that are used to treat pulmonary edema may vary based on the origin or cause of the edema. Pulmonary edema of a cardiac origin may be treated by prescribing medication to the patient such as diuretics, fluid pills, or other medications. These medications may decrease the fluid retained in the heart or lungs. Pulmonary edema of a non-cardiac origin may be treated differently. For example, pulmonary edema that is not from a cardiac-related cause may be treated by inserting a needle or catheter into the pleural space surrounding the lungs and draining the excess fluid.
Known systems and methods do not provide a satisfactory ability to identify the cause of pulmonary edema. For example, known defibrillators and external devices that are communicatively coupled with the defibrillators do not distinguish among the various origins or causes of pulmonary edema. As the proper treatment for pulmonary edema depends on the origin of the edema, a need exists for systems and methods that distinguish between the potential causes or origins of the edema.